This application relates to a liquid crystal-based detector card for detecting leakage from microwave generating devices such as microwave ovens.
Liquid crystals undergo color changes, sometimes called "color play," depending on the temperature of the crystals. This phenomenon has been employed in the construction of microwave detectors, e.g., in U.S. Pat. No. 4,051,435, incorporated herein by reference. The present application also makes use of this phenomenon, but provides reduced risk of error and improved sensitivity due to the unique arrangement of test and control liquid crystal indicators.